Coating composition comprising fluorochemical polyether silane polycondensate and use thereof

Abstract

A composition comprising the condensation product of a least one fluorochemical polyether silane compound having a polyfluoropolyether segment and at least two hydrolysable silane groups per molecule, with one or more non-fluorinated compounds having at least two hydrolysable groups per molecule, and the reaction product thereof, is disclosed. The composition provides durable water, oil and stain repellency to a substrate.

1. A composition comprising the reaction product obtained after a substantially complete condensation reaction of:
 A. at least one fluorochemical polyether silane compound of the formula:
   R f —[Q-CR 2 Si(Y) 3-x (R 1 ) x ] z   
 
 
       wherein R f  represents a multivalent polyfluorepolyother segment, Q represents an organic divalent linking group, R 1  represents a C 1 –C 8  alkyl group, Y represents a hydrolysable group independently selected from a halide group, an alkoxy group, an acyloxy group, and an aryloxy group, R represents hydrogen or an alkyl group of 1 to 4 carbon atoms whereby the R groups may be the same or different, z is 2, 3 or 4 and x is 0 or1; and
 B. a substantial amount of one or more tetraalkoxysilanes. 
 
     
     
       2. A composition according to  claim 1  wherein said component (B) further comprises a compound according to the formula:
   (R 2 ) q M(Y 1 ) p-q   
 
       wherein R 2  represents a non-hydrolysable group, M represents an element selected from the group consisting of Si, Ti, Zr, B, Al, Ge, V, Pb, Sn and Zn, p is 3 or 4 depending on the valence of M, q is 0,1 or 2, and Y 1  represents a hydrolysable group. 
     
     
       3. The composition according to  claim 2 , wherein said compound (R 2 ) q M(Y 1 ) p-q  is a trialkoxy silane. 
     
     
       4. A composition according to  claim 1  wherein said reaction product is a reaction product obtained from a substantially complete condensation reaction of said components (A) and (B) and further a crosslinking agent (C). 
     
     
       5. A composition according to  claim 4  wherein the crosslinking agent (C) is a compound of an element M 1  that is selected from the group consisting of Si, Ti, Zr, B, Al, Ge, V, Pb, Sn and Zn, said crosslinking agent (C) further having at least one hydrolysable group and at feast one reactive functional group per molecule that is capable of engaging in a crosslinking reaction. 
     
     
       6. The composition according to  claim 1 , wherein the polyfluoropolyether segment includes perfluorinated repeating units selected from the group consisting of —(C 2 F 2n O)—, —(CF(Z)O)—, —(CF(Z)C n F 2n O)—, —(C n F 2n CF(Z)O)—, —(CF 2 CF(Z)O)—, and combinations thereof, wherein Z is a perfluoroalkyl group, an oxygen-substituted perfluoroalkyl group, a perfluoroalkoxy group, or an oxygen-substituted perfluoroalkoxy group, all of which can be linear, branched, or cyclic, and have 1 to 9 carbon atoms and 0 to 4 oxygen atoms and wherein n is a number from 1 to 12 inclusive. 
     
     
       7. The composition according to  claim 1 , wherein the weight ratio of component (A) to component (B) is 1:1 to 1:20. 
     
     
       8. A coating composition comprising 0.01 to 5 weight percent of the composition of  claim 1  and an organic solvent. 
     
     
       9. A coated substrate comprising a coating derivable from the composition of  claim 1 . 
     
     
       10. Method of treating a substrate, comprising the steps of coating at least part of the surface of said substrate with a coating composition as defined in  claim 1 . 
     
     
       11. Method according to  claim 10  wherein said substrate is glass, ceramic, metal or a polymeric substrate. 
     
     
       12. Method according to  claim 10  wherein said method further involves the step of subjecting the coated substrate to an elevated temperature in the range of 40 to 400° C. 
     
     
       13. Process for the preparation of a perfluoropolyether condensation product, the process comprising the steps of admixing:
 A. at least one fluorochemical polyether silane compound of the formula:
   R f —[Q-CR 2 Si(Y) 3-x (R 1 ) x ] z   
 
 
       wherein R f  represents a multivalent polyfluoropolyether segment, Q represents an organic divalent linking group, R 1  represents a C 1 –C 8  alkyl group, Y represents a hydrolysable group independently selected from a halide group, an alkoxy group, an acyloxy group, and an aryloxy group, R represents hydrogen or an alkyl group of 1 to 4 carbon atoms whereby the R groups may be the same or different, z is 2, 3 or 4 and x is 0 or 1; and
 B. a substantial amount of one or more tetraalkoxysilanes; and 
 C. optionally a crosslinking agent of an element M 1  that is selected from the group consisting of Si, Ti, Zr, B, Al, Ge, V, Pb, Sn and Zn, said crosslinking agent further having at least one hydrolysable group and at least one reactive functional group per molecule that is capable of engaging in a crosslinking reaction; 
 
       and reacting the components until substantial completion of the reaction is detected. 
     
     
       14. Process according to  claim 13  wherein said components (A), (B) and optionally (C) are further admixed with water and an acid or base catalyst.